The quantitative determination of analytes in body fluids is of great importance in the diagnoses and maintenance of certain physiological abnormalities. For example, lactate, cholesterol and bilirubin are monitored in certain individuals. In particular, it is important that individuals with diabetes frequently check the glucose level in their body fluids to regulate the glucose intake in their diets. The results of such tests can be used to determine what, if any, insulin or other medication needs to be administered. In one type of blood-glucose testing system, test sensors are used to test a sample of blood.
A test sensor contains biosensing or reagent material that reacts with, for example, blood glucose. For example, the testing end of the sensor may be adapted to be placed into contact with the fluid being tested (e.g., blood) that has accumulated on a person's finger after the finger has been pricked. The fluid may be drawn into a capillary channel that extends in the sensor from the testing end to the reagent material by capillary action so that a sufficient amount of fluid to be tested is drawn into the sensor. The tests are typically performed using a meter that receives the test sensor into a test-sensor opening and applies optical or electrochemical testing methods.
The accuracy of such testing methods however may be affected by the temperature of the test sensor. For example, the result of the chemical reaction between blood glucose and a reagent on a test sensor may vary at different temperatures. To achieve an accurate reading, the actual measurement is corrected based on the actual sensor temperature, taken right before the reaction begins. The conventional way to measure the test sensor temperature involves reading a resistive value from a thermistor placed near the test-sensor opening. The thermistor resistance recalculates the chemical reaction result. This correction method is based on an assumption that a sensor temperature is the same as the thermistor temperature placed near the test-sensor opening. In reality, however, the thermistor, which is typically located on a printed circuit board, actually provides the temperature of the meter. Because the temperature of the meter can be very different from the test sensor temperature, the analyte measurement may be inaccurate.